Hollow BiFeO3 nanoparticles were synthesized by an electrospray route for the first time. The
phase purity and structure have been investigated by x-ray diffraction and Raman spectroscopy.
Transmission and scanning electron microscope investigations revealed that the as-obtained
BiFeO3 hollow spheres were polycrystalline, with a shell thickness of 35 nm. The formation
mechanism can be possibly explained by Ostwald ripening. Raman spectra have verified decreased
vibrational frequencies in BiFeO3 nanoparticles. These hollow and core-shell multiferroic
nanoparticles exhibit significantly enhanced ferromagnetism from 5 to 600 K due to a broken spiral
spin structure. The ferroelectricity of hollow BiFeO3 particles exhibits a lower switching electric
field, which is confirmed by Kelvin probe force microscopy.